1800 is INNER
900 is OUTER
Lets take a look at following cases:
CASE-1: TCH ASSIGNMENT
How do BSC came to know that at this moment the Rxlevel of 1800 is so and so? I mean who is going to report this to BSC? Unless BSC knows the Rxlevel of 1800, i think it will not be possible for the BSC to decide whether it is > threshold or not. So, how do the case 1 : Alloting a TCH on INNER zone will be done.
CASE-2: INTRACELL HANDOVER
The call is on OUTER. ie 900.
Again the same situation as with the case-1.
* BCCH is on 900…OUTER ZONE
* 1800…INNER ZONE is having only TCH.
Who is going to perform the measurements on the TCH of 1800, as the TCH is yet to be allocated.